Stud and shoe provided with the studs

ABSTRACT

The invention provides a stud for a shoe, light in weight, and having a long service life and excellent abrasion resistance, and a shoe using the same. The stud for the shoe comprises a central protruding member, a seating plate, and peripheral binding members. The seating plate is formed of a metallic material, and the central protruding member or the peripheral binding members are formed of RB ceramic or CRB ceramic. The shoe is fabricated by securely attaching the studs to an outsole thereof.

FIELD OF THE INVENTION

[0001] The present invention relates to a stud for a shoe, and a shoeusing the studs, and more specifically, to a stud for a shoe, light inweight, and having not only an excellent non-skid performance orgripping performance but also an excellent walking performance on a hardsurface of a road such as a pavement, a concrete road, and so forth, oron a hard floor, suitable, particularly, for use in sports shoes such asgolf shoes, soccer shoes, or baseball shoes, spikes, non-skid shoes foruse in cold districts, and so forth, and a shoe using the same.

BACKGROUND OF THE INVENTION

[0002] Studs for shoes, for example, spikes, especially, spikes for usein sports shoes and non-skid shoes, are required to have excellentgripping performance and non-skid performance, and such performances areimportant from the viewpoint of providing comfortableness in wearing andsafety as well.

[0003] As a constituent material of such studs, for example, spikes, andso forth, use is made of a corrosion resistant steel such as stainlesssteel and carbon steel, a metallic material such as titanium, and soforth, and a hard resin.

[0004] The metallic material is superior in strength, however, it is toohard as the constituent material of the studs to avoid impact resistancesuch as a feeling of a thrust coming up from below when a user iswalking on a hard surface of a pavement or a concrete road, therebyaggravating discomfort of the user. In addition, there are also problemsthat a steel based material used in the studs renders shoes heavierbecause of its high specific gravity while titanium is costly. Further,there is a problem with the hard resin that it has poor abrasionresistance and a short durability.

SUMMARY OF THE INVENTION

[0005] It is an object of the invention to overcome such drawbacks ofthe conventional studs as described above, and to provide a stud for ashoe, light in weight, having a long service life and excellent abrasionresistance, and a shoe using the same.

[0006] RB ceramic for us in carrying out an embodiment of a studaccording to the invention is a carbonaceous material obtained byutilizing rice bran, produced in quantity of 900,000 tons a year inJapan and in quantity of as much as 33 million tons a year throughoutthe world, and has been well known by researches carried out by Mr.Kazuo Hokkirigawa, the first inventor of the present invention (refer to“Functional Material”, May issue, 1997, Vol.17, No. 5, pp. 24˜28).

[0007] In this literature, reference is made to a carbon material(hereinafter referred to as RB ceramic) and the preparation thereof, inwhich the carbonaceous material is obtained by mixing and kneadingdefatted bran derived from rice bran with a thermosetting resin beforekneading, followed by drying a compact obtained by pressure forming akneaded mixture, and subsequently, baking the dried compact as dried inan atmosphere of an inert gas.

[0008] The RB ceramic and a new ceramic (CRB ceramic as described lateron) representing an improvement on the RB ceramic, for use in anembodiment of a stud according to the invention, are ceramic materialsfriendly to nature, obtained by using rice bran as raw material, and bymixing defatted bran derived from the rice bran with a thermosettingresin before baking a mixture. These materials have excellent propertiesas described below:

[0009] Higher hardness

[0010] Smaller expansion coefficient

[0011] porous micro structure

[0012] good electric conductivity

[0013] small specific gravity and light weight

[0014] very small friction coefficient

[0015] excellent abrasion resistance

[0016] easy to form and easy to fabricate in a die

[0017] ceramic materials having varying characteristics can be producedby blending with various kinds of resins

[0018] the materials being made of rice bran, they have little adverseeffect on global environment, leading to conservation of naturalresources.

[0019] The new ceramic described above is an improved material of the RBceramic, and is a class of ceramic (referred to as the CRB ceramic) thatis obtained by mixing defatted bran derived from rice bran with athermosetting resin. More particularly, the defatted bran derived fromrice bran and a thermosetting resin are mixed and kneaded, subjecting akneaded mixture thus obtained to a primary baking in an inert gas at atemperature in a range of 700 to 1000° C., and pulverizing the kneadedmixture after the primary baking into carbonized powders passing througha 100-mesh sieve.

[0020] The carburized powders and the thermosetting resin are furthermixed and kneaded, pressure forming a kneaded mixture into a compact ata pressure in a range of 20 to 30 MPa, and subjecting the compact againto a heat treatment in an inert gas atmosphere at a temperature in arange of 100 to 1100° C. The CRB ceramic differs largely from the RBceramic in that, in contrast with the RB ceramic having a contractionratio of the dimensions of the compact obtained by pressure forming tothose of a finished compact at as high as 25%, the CRB ceramic has acontraction ratio in the order of not more than 3%, which is very small.

[0021] The inventors have discovered that these ceramic materials arelight in weight and have a long service life, excellent abrasionresistance, insusceptibilty to damage, and excellent workability, sothat the same are suitable as a constituent material of a stud, for usein combination with a metallic material. The invention has beendeveloped based on such knowledge as described above.

[0022] More specifically, the embodiment of the stud according to theinvention comprises a central protruding member 1, a seating plate 2,and peripheral binding members 3, wherein the central protruding member1 and the seating plate 2 are formed of a metallic material,respectively, and the peripheral binding members 3 are formed of the RBceramic or the CRB ceramic.

[0023] Further, with a stud according to another embodiment of theinvention, the central protruding member 1 and the peripheral bindingmembers 3 may be formed of the RB ceramic or the CRB ceramic.

[0024] Furthermore, the invention provides a shoe using these studs fora shoe.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a perspective view of an embodiment of a stud accordingto the invention;

[0026]FIG. 2 is a cross sectional view of the stud taken on line b-b inFIG. 1;

[0027]FIG. 3 is a side view of the stud shown in FIG. 1;

[0028]FIG. 4 is a perspective view of a shoe with the studs securelyattached thereto; and

[0029]FIG. 5 is a side view of a shoe with the studs securely attachedthereto.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] RB ceramic material and CRB ceramic material for use in carryingout an embodiment of a stud according to the invention are made ofdefatted bran derived from rice bran, as a main raw material, and athermosetting resin.

[0031] The defatted bran may be of either a local domestic origin or aforeign origin regardless of the kind of rice.

[0032] Further, for the thermosetting resin, any thermosetting resin maybe used as long as it has thermosetting property, and typical examplesthereof include phenol resin, diaryl phthalate resin, unsaturatedpolyester resin, epoxy resin, polyimide resin, and triazine resin. Inparticular, phenol resin is preferably used.

[0033] Furthermore, a thermoplastic resin, such as a polyamide and soforth, can be used in combination with the thermosetting resin providedthat it is used without departing from the spirit and scope of theinvention.

[0034] A mixing ratio of the defatted bran to the thermosetting resin is50 to 90:50 to 10 by weight, however, the mixing ratio of 70 to 80:30 to20 is preferably adopted.

[0035] Next, a method of producing the CRB ceramic material is brieflydescribed hereinafter. The method comprises the steps of mixing andkneading defatted bran derived from rice bran with a thermosetting resinbefore kneading, subjecting a kneaded mixture thus obtained to a primarybaking in an inert gas at a temperature in a range of 700 to 1000° C.,pulverizing the kneaded mixture after the primary baking into carbonizedpowders, mixing and kneading the carbonized powders with a thermosettingresin before kneading, pressure forming a kneaded mixture thus obtainedinto a compact at a pressure in a range of 20 to 30 MPa, and subjectingthe compact again to a heat treatment at a temperature in a range of 100to 1100° C. in an inert gas atmosphere.

[0036] A thermosetting resin in a liquid state, having a relativelysmall molecular weight, is desirable as the thermosetting resin for usein the primary baking.

[0037] A rotary kiln is normally used in carrying out the primarybaking, and baking time is in a range of 40 to 120 min. A mixing ratioof the carbonized powders obtained by the primary baking to thethermosetting resin is 50 to 90:50 to 10 by weight, however, the mixingratio of 70 to 80:30 to 20 is preferably adopted.

[0038] The kneaded mixture of the carbonized powders and thethermosetting resin is pressure formed into the compact at a pressure ina range of 20 to 30 MPa, preferably, in a range of 21 to 25 MPa. A diefor use is preferably at a temperature of about 150° C.

[0039] For the heat treatment, a well controlled electric furnace isnormally employed, and heat treatment time is in a range of about 60 to360 min.

[0040] A heat treatment temperature is preferably in a range of 100 to1100° C., and a warming rate up to heat treatment temperature isrequired to be relatively moderate up to 500° C. In terms of morespecific-values, the warming rate is in a range of 0.5 to 2° C./min, andis preferably about 1° C.

[0041] Further, in lowering the temperature of the compact after bakedby the heat treatment in this manner, a cooling rate is required to berelatively moderate until reaching 500° C. Upon the temperature droppingbelow 500° C., the compact is left to cool by itself.

[0042] In terms of more specific values, the cooling rate is in a rangeof 0.5 to 4° C./min, and is preferably about 1° C./min.

[0043] Further, the inert gas used at the time of the primary baking aswell as the secondary heat treatment may be any gas selected from thegroup consisting of helium, argon, neon, and nitrogen gas, however,nitrogen gas is preferably used.

[0044] The stud according to the embodiment of the invention can be usedas appropriate in combination with a conventional metal based stud, ahard resin based stud, a stud made of other synthetic resins, or a studmade of an elastic or a soft material, such as natural rubber, syntheticrubber, and other elastomers.

[0045] Further, for an outsole of a shoe, use is preferably made of asynthetic resin, a synthetic rubber, natural rubber, or a syntheticelastomer, in common use as a conventional material for the outsole.

[0046] The synthetic resin may be any synthetic resin, if hard andstrong to a degree, selected from the group consisting of hardpolyethylene, polyolefin such as polypropylene, polyamide such as nylon66, polycarbonate, and so forth.

[0047] Further, examples of the synthetic rubber include butadienerubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber,isoprene rubber, chloroprene rubber, butyl rubber,ethylenepolypropylene-diene rubber, acrylic rubber, urethane rubber, andso forth.

[0048] With the stud according to the embodiment of the invention,protruded parts thereof are preferably made up of a main protrudingmember 1 disposed at the center, and protrusions of peripheral bindingmembers 3 disposed around the main protruding member 1, as shown inFIGS. 1 to 3, from the viewpoint of avoiding concentration of force onthe main protruding member 1 at the center when shoes are worn by auser. Further, the main protruding member 1 can be formed in the shapeof a pointed conical protrusion although not shown in the figures.

[0049] According to the invention, the central protruding member 1 and aseating plate 2 can be formed of a metallic material, and the peripheralbinding members 3 can be formed of the RB ceramic or the CRB ceramic, orthe central protruding member 1 and the peripheral binding members 3 canbe formed of the RB ceramic or the CRB ceramic.

[0050] Otherwise, the central protruding member 1 and the seating plate2 can be formed of a metallic material, and integrally with each other,for use in combination with the peripheral binding members 3 formed ofthe RB ceramic or the CRB ceramic.

[0051] Further, the seating plate 2 can be formed of a metallicmaterial, and the central protruding member 1 and the peripheral bindingmembers 3 can be formed of the RB ceramic or the CRB ceramic, andintegrally with each other in such a way as to wrap up the seating plate2. In this case, the central protruding member 1 may be changed in shapedepending on stress to which the same is subjected. For example, anangularity of the conical protrusion thereof can be changed in a rangeof an acute angle to an obtuse angle to prevent the central protrudingmember 1 from being excessively loaded. Furthermore, it is also possibleto render the apex of the conical protrusion flat so as to cause a loadimposed thereon to be dispersed or to form the apex thereof in the shapeof a plurality of conical protrusions as ranged.

[0052] Further, the RB ceramic or the CRB ceramic for use in carryingout the embodiment of the stud according to the invention is light inweight, and has a characteristic of excellent abrasion resistance,however, one subjected to the secondary heat treatment at a hightemperature has susceptibility to buckling when a large load is imposedthereon because it is slightly lower in mechanical strength. With thepresent invention, it is therefore preferable to form the seating platefrom a metallic material having high mechanical strength for use incombination with the central protruding member and the peripheralbinding members, formed from a metallic material or hard resin otherthan the metallic material.

[0053] In the case of using the CRB ceramic in carrying out theembodiment of the stud according to the invention, the CRB ceramicobtained by baking at a low temperature lower than about 500° C.generally has characteristics such as toughness and excellent mechanicalproperty while the same obtained by baking at a high temperature notlower than 600° C. generally has characteristics such as high porosity,high hardness, and light weight, so that it is possible to makeselective use thereof depending on required properties of a given stud.

[0054] The embodiments of the invention are summed up as follows:

[0055] (1) A stud for a shoe, comprising a central protruding member, aseating plate, and peripheral binding members, wherein the seating plateis formed of a metallic material, and the central protruding member orthe peripheral binding members are formed of RB ceramic or CRB ceramic.

[0056] (2) A stud for a shoe as set forth in item (1) above, wherein theseating plate and the central protruding member are formed of the RBceramic or the CRB ceramic, integrally with each other.

[0057] (3) A stud for a shoe as set forth in item (1) above, wherein theseating plate, the central protruding member, and the peripheral bindingmembers are formed of the RB ceramic or the CRB ceramic, integrally witheach other.

[0058] (4) A stud for a shoe as set forth in any one of items (1) to (3)above, wherein the CRB ceramic is obtained by a secondary heat treatmentapplied at a temperature in a range of 200 to 1000° C.

[0059] (5) A stud for a shoe as set forth in any one of items (1) to (4)above, wherein the peripheral binding members are each provided with aperipheral protrusion lower in profile than a protrusion of the centralprotruding member.

[0060] (6) A stud for a shoe as set forth in any one of items (1) to (5)above, wherein the protrusion of the central protruding member has anangularity of an optional angle in a range of an acute angle to anobtuse angle

[0061] (7) A stud for a shoe as set forth in any one of items (1) to (6)above, wherein the protrusion of the central protruding member is in anyone shape selected from the group of a shape having one apex of theprotrusion and a shape having a plurality of apexes thereof.

[0062] (8) A shoe provided with a plurality of studs each comprising acentral protruding member made of metal, disposed on parts of an outsolethereof, and a plurality of the studs as set forth in any one of items(1) to (7) above, disposed on other parts of the outsole, eachcomprising the central protruding member made of the RB ceramic or theCRB ceramic, and lower in profile than the studs comprising the centralprotruding member made of metal.

[0063] (9) A shoe as set forth in item (8) above, for use in golf,soccer, baseball or track.

[0064] Embodiments

[0065] (Production of a Precursor of the CRB Ceramic)

[0066] The precursor of the CRB ceramic for use in fabrication of aconstituent member making up a main protruded part of a stud for a shoewas produced as follows:

[0067] 75 kg of defatted bran derived from rice bran was mixed andkneaded with 25 kg of phenol resin (resol) in liquid state while heatingboth to 50 to 60° C. A plastic and homogeneous mixture was obtained.

[0068] The mixture was subjected to a primary baking at 900° C. in anitrogen atmosphere in a rotary kiln for 60 minutes. Subsequently, abaked product thus obtained was screened through a 100-mesh sieve,thereby obtaining carbonized powders 50 to 250 mm in particle diameter.

[0069] 75 kg of thus obtained carbonized powder was mixed and kneadedwith 25 kig of phenol resin (resol) in solid state while heating both to100 to 150° C., thereby obtaining the precursor of the CRB ceramic,composed of a plastic homogeneous mixture.

[0070] The embodiments of the invention are described hereinafter withreference to the accompanying drawings

[0071] Embodiment 1

[0072] There is shown an example of fabricating a stud (wherein acentral protruding member 1 and a seating plate 2 are made of stainlesssteel, and peripheral binding members 3 are made of the CRB ceramic)according to an embodiment 1 of the invention.

[0073] The stud comprises a central protruding member 1 and a seatingplate 2, both made of stainless steel, and peripheral binding members 3made of the CRB ceramic. The central protruding member 1 is comprised ofa stud protrusion 11 substantially in the shape of a hexagonal prism,and a flange 12 circular in shape, provided integrally therewith, aroundthe periphery of the lower end thereof. The flange 12 is provided with aplurality of holes 13 defined therein, and the stud protrusion 11 isprovided with slender grooves 14, defined in the bottom face thereof,for fitting onto small protrusions 22 of the seating plate 2.

[0074] The seating plate 2 comprises a disk 21, a plurality of the smallprotrusions 22 protruding from the upper face of the disk 21, and athreaded part 23 for fixedly attaching the stud to an outsole of theshoe, provided on the underside of the disk 21 in such a way as to hangtherefrom. The small protrusions 22 are inserted into the slendergrooves 14 of the stud protrusion 11, respectively. The disk 21 isprovided with a plurality of holes defined at positions thereon,corresponding to respective positions of the plurality of the holes 13of the flange 12.

[0075] The central protruding member 1 and the seating plate 2 arelinked together with the peripheral binding members 3 in the followingmanner. First, the seating plate 2 is covered directly by the centralprotruding member 1, and the stud protrusion 11 is brought into intimatecontact with the disk 21. Since a height of the small protrusions 22 ofthe seating plate 2 is substantially equivalent to a depth of theslender grooves 14 of the stud protrusion 11, both parts come intointimate contact with each other.

[0076] Subsequently, the central protruding member 1 integrated with theseating plate 2 excluding the threaded part 23 is placed inside a die inthe shape of the central protruding member 1 and the seating plate 2excluding the threaded part 23, and the precursor of the CRB ceramic isinjected therein to be pressure formed into a compact in the shape shownin FIGS. 1 and 2 at a pressure of 22 MPa. The die for use is at atemperature of about 150° C. The compact is taken out of the die, and issubjected to a heat treatment in a nitrogen atmosphere whereby thecompact is heated at a warming rate of 1° C. min up to 500° C., held at500° C. for 60 min heat treated at 800° C. for about 120 min beforelowering the temperature of the compact at a cooling rate in a range of2 to 3° C./min until reaching 500° C. and upon the temperature droppingbelow 500° C., the compact is left to cool by itself. The thickness ofthe peripheral binding members 3, on the side of the seating plate 2, isrendered thicker on the peripheral side of the disk 21, and thinner onthe center side thereof.

[0077] A protrusion of the respective peripheral binding members 3 ismade up of a protrusion in the shape of an elliptical hemisphere, and aprotrusion in the shape of a truncated cone, disposed at the center ofthe apex of the former, and is as shown in FIG. 1 to FIG. 3, arranged soas to surround the stud protrusion 11 which is the protruded part of thecentral protruding member 1, and so as to be lower in profile than theprotruded part described.

[0078] The central protruding member 1 is securely bonded to the seatingplate 2 with the peripheral binding members 3, and in addition,concentration of force towards the central protruding member 1 isprevented by the protrusion of the respective peripheral binding members3. Furthermore, the binding members 3 can fulfill a function similar tothat of a packing upon attaching the stud to the outsole of a shoe byrendering the thickness thereof, on the side of the seating plate 2,thicker on the peripheral side of the disk 21, and thinner on the centerside thereof.

[0079] Embodiment 2

[0080] (A Central Protruding Member and a Seating Plate are Formed ofMetal, and Integrally with Each Other)

[0081] A stud is fabricated in a manner similar to that for the studaccording to the embodiment 1 of the invention except that use is madeof a stainless steel structure fabricated by forming the centralprotruding member integrally with the seating plate in the die.

[0082] Embodiment 3

[0083] (An Embodiment wherein a Central Protruding Member and PeripheralBinding Members are Formed of the CRB Ceramic, Integrally with EachOther)

[0084] A seating plate 2 is prepared, and is placed in a diecorresponding to the shape of a central protruding member 1 andperipheral binding members 3 (a threaded part 23 is not placed in thedie).

[0085] Subsequently, the same precursor of the CRB ceramic as producedaccording to the embodiment 1 is pressure formed into a compact at apressure of 25 MPa. The die for use is at a temperature of about 150° C.

[0086] The compact is taken out of the die, and is subjected to a heattreatment in a nitrogen atmosphere whereby the compact is heated at awarming rate of 1° C./min up to 500° C., held at 500° C. for 60 min heattreated at 900° C. for about 120 min. Thereafter, the temperature of thecompact is lowered at a cooling rate in a range of 2 to 3° C./min untilreaching 500° C. and upon the temperature dropping below 500° C., thecompact is left to cool by itself.

[0087] A stud is obtained wherein the seating plate 2 made of metal isformed integrally with the central protruding member 1 and theperipheral binding members 3, both made of the CRB ceramic.

[0088] Embodiment 4

[0089] (Fabrication of Golf Shoes)

[0090] As shown in FIG. 4, the stud fabricated according to theembodiment 1 or 2 is screwed into a female thread 41 of a fixture mount4 of an outsole 5 of a shoe. The constituent material of the outsole 5is hard rubber. Golf shoes comfortable to wear, having excellentgripping performance and non-skid performance are obtained. In thefigure, a central protruding member 1 is not shown.

[0091] Embodiment 5

[0092] (Fabrication of Golf Shoes Using Studs Made of the CRB Ceramic inCombination with Studs Made of Metal)

[0093] As shown in FIG. 5, with a golf shoes according to an embodiment5, spikes P made of stainless steel, taller than studs made of the CRBceramic, are disposed in parts of an outsole 5, on which the weight of auser rests while studs S, as other studs, comprising the centralprotruding member formed of the CRB ceramic, according to the embodiment3, are disposed.

[0094] Golf shoes, light in weight and comfortable to wear, are obtainedwherein a good gripping effect of the spikes made of stainless steel isexhibited when a user is walking on a concrete or cart road, and anexcellent non-skid performance effected by gripping of the grass withthe studs made of the CRB ceramic is exhibited when the user is walkingon the grass.

[0095] Thus, the stud and shoes using the studs according theembodiments of the invention are able to provide shoes light in weightand comfortable to wear, having a long service life, an excellentabrasion resistance, excellent gripping performance, and excellentnon-skid performance.

What is claimed is:
 1. A stud for a shoe, comprising: a centralprotruding member; a seating plate; and peripheral binding members;wherein the seating plate is formed of a metallic material, and thecentral protruding member or the peripheral binding members are formedof RB ceramic or CRB ceramic.
 2. A stud for a shoe according to claim 1,wherein the seating plate and the central protruding member are formedof the RB ceramic or the CRB ceramic, and integrally with each other. 3.A stud for a shoe according to claim 1, wherein the seating plate, thecentral protruding member, and the peripheral binding members are formedof the RB ceramic or the CRB ceramic, and integrally with each other. 4.A stud for a shoe according to any one of claims 1 to 3, wherein the CRBceramic is obtained by a secondary heat treatment applied at atemperature in a range of 200 to 1000° C.
 5. A stud for a shoe accordingto any one of claims 1 to 4, wherein the peripheral binding members areeach provided with a peripheral protrusion lower in profile than aprotrusion of the central protruding member.
 6. A stud for a shoeaccording to any one of claims 1 to 5, wherein the protrusion of thecentral protruding member has an angularity of an optional angle in arange of an acute angle to an obtuse angle.
 7. A stud for a shoeaccording to any one of claims 1 to 6, wherein the protrusion of thecentral protruding member is in any one shape selected from the group ofa shape having one apex of the protrusion and a shape having a pluralityof apexes thereof.
 8. A shoe provided with a plurality of studs eachcomprising a central protruding member made of metal, disposed on partsof an outsole thereof, and a plurality of the studs according to any oneof claims 1 to 7, disposed on other parts of the outsole, eachcomprising the central protruding member made of the RB ceramic or theCRB ceramic, and lower in profile than the studs comprising the centralprotruding member made of metal.
 9. A shoe according to claim 8, for usein golf, soccer, baseball or track.